Sauté Veggies: In a large cast iron skillet, add 1 tablespoon oil to coat the bottom of the pan and bring to medium-high heat. Add 2 teaspoons garlic & 1 teaspoon ginger; stir to allow them to cook until aromatic, about 1-2 minutes. Add diced onion, carrots, & water chestnuts (if using) to the hot pan; cook 2-3 minutes moving around the pan. Add additional oil, if pan gets dry.
Brown Beef: Add ground beef, break apart and move around pan with spatula, allowing to cook fully. Season with a generous pinch of salt and pepper, plus 1/4 teaspoon red pepper flakes (if using).
Make Sauce: Put the Sauce ingredients in a small bowl and whisk together until it is fully combined. Add Sauce to the ground beef and mix on medium-high heat. It will thicken quickly, about 1 minute.
Serve: Take a piece of butter lettuce and top with rice and then some of the ground beef mixture. Squeeze fresh lime juice on top, add green onions, cilantro, and any other toppings.
Notes
Ground Beef: feel free to sub ground turkey or ground chicken for the beef, but just be aware that it has a more mild flavor, so you may need to adjust the seasonings.
Tapioca Starch: option to use arrowroot starch, instead of tapioca starch, if you need to, but tapioca starch tends to work the best.
Rice: to be Paleo/Whole30 compliant you will want to use a cauliflower rice, but if that isn't a concern for you feel free to use white rice, brown rice, any variety!
Nutrition Info was calculated with cauliflower rice, not regular rice.